In a known locking system of this kind (as described in DE 27 29 770 C2) two rows of notches in a channel are configured in such a manner that each notch is designed as a rectangular passage and lies in the transitional region from a yoke section to one of two adjacent legs. The two locking bodies are formed by the two arms of a Y-like, plate-shaped stamping, which can be swivelled around an axis extending parallel to the channel, and are slidable at right angles to the channel. For all notches the length measured in the longitudinal direction of the bar, thus the direction of adjustment, must correspond to the sum of the width of one of the webs, existing between two successive notches of the same row, and twice the value of the thickness of the stamping forming the locking bodies, said thickness being measured in the direction of adjustment.